The invention relates generally to a windshield wiper having a connection piece which can be connected to a wiper arm and which is connected to a flat bar, and which has a wiper strip which is connected to the flat bar and can be pressed against the window to be wiped. Such windshield wipers are known for instance from European Patent EP 0 528 643, and they are distinguished over conventional wiper blades in that instead of a complicated support bracket frame, the contact pressure exerted by the wiper arm is transmitted to the wiper strip via a so-called flat bar. The flat bar as a rule comprises a pre-curved spring steel or a plastic rod. The wiper strip is glued to the flat bar, or it is received by the flat bar in the recesses intended for it.
For windshield wipers that have support bracket frames, it is known from German Patent Disclosure DE-OS 26 15 292 to form the support bracket of a wiper blade from two bracket parts, which have recesses and protrusions graduated in shoulderlike fashion. In the assembled position, the protrusions engage the recesses and are rotatably connected to one another via a pivot bolt that penetrates the protrusions. By way of the joint thus formed, the bracket parts can be pivoted relative to one another. In this way, an easily installed support bracket frame for a wiper blade is obtained.
The windshield wiper of the present invention has the advantage that because of the joint placed in the flat bar, the windshield wiper can be adapted exactly to even an extreme window curvature. The flat bar which is curved in the unloaded state must have a course of curvature in the unloaded position that is maintained precisely during wiping operation for a predetermined contact pressure distribution. By splitting that flat bar into at least two pieces, the part size that has to be machined and, thus, tool costs are less, and conversely the part tolerances to be expected are easier to adhere to.
From an assembly standpoint, it is especially simple if the joint is disposed in the region of the connection piece. The connection piece can then in turn take on a guide, stop and retention function. If one or more joints are disposed outside the region of the connection piece, then the flat bar can be adapted even more precisely to the curved course of the window to be wiped.
The contact pressure distribution which is definitively responsible for the wiping quality can be optimally set if the pieces, which are spring-connected to the joint or joints, are spring-loaded relative to one another. The joints can then be pressed in prestressed fashion against the surface of the window to be wiped. The prestressing can be composed of the intrinsic elasticity of the spring bar pieces on the one hand and of the spring-mounted joints on the other.
An especially simple stop to prevent excessive bending backward of the joint or joints is achieved if the two flat bar pieces that form the joint each have at least one extension that protrudes past the respectively other piece. The extensions are then braced on the respectively other pieces and prevent the flat bar from being hinged away from the window. The spring support of the joints can be achieved especially simply by placing an elastic element between each piece and the extension that protrudes past the piece. The elastic element is formed in the simplest case by the rubber of the wiper strip. In this way, an extremely economical flat bar wiper blade is made available that by way of the prestressing and the choice of spring furnishes an optimal distribution of contact pressure.